Liquid crystal panel control circuit having reset circuit and liquid crystal display driving circuit with same

Abstract

An exemplary liquid crystal panel control circuit ( 20 ) includes a direct current converting circuit ( 23 ). The direct current converting circuit includes a comparator ( 231 ), a reset circuit ( 232 ), and a DC-to-DC converting circuit ( 233 ) connected in series. The liquid crystal panel control circuit can return to an initial status from a protection status by the reset circuit.

1 . A liquid crystal panel control circuit, comprising:
 a direct current converting circuit, the direct current converting circuit comprising a comparator, a reset circuit, and a DC-to-DC converting circuit connected in series.   
   
   
       2 . The liquid crystal panel control circuit as claimed in  claim 1 , wherein the comparator has a predetermined reference voltage, if the comparator receives a direct current voltage lower than the reference voltage, the comparator outputs a low level voltage to the reset circuit, and the reset circuit does not work, if the comparator receives a direct current voltage higher than the reference voltage, the comparator outputs a high level voltage to the reset circuit, and the reset circuit outputs a high level voltage to reset the DC-to-DC converting circuit, that is, the DC-to-DC converting circuit is returned to an initial status. 
   
   
       3 . The liquid crystal panel control circuit as claimed in  claim 2 , further comprising a timing control circuit connected to the direct current converting circuit. 
   
   
       4 . The liquid crystal panel control circuit as claimed in  claim 3 , wherein the timing control circuit comprises a plurality of electro static discharge (ESD) lines, each ESD line comprising a first diode and a second diode in series, positive electrodes of the second diodes being connected to ground, negative electrodes of the first diodes are connected to the direct current converting circuit. 
   
   
       5 . The liquid crystal panel control circuit as claimed in  claim 4 , wherein the predetermined reference voltage satisfies a relationship: Vc-0.7V<Vr<Vc, wherein Vc represents direct current voltage when the DC-to-DC converting circuit works normally, Vr represents the predetermined reference voltage, 0.7V is equal to a voltage drop when the first diodes are turned on. 
   
   
       6 . The liquid crystal panel control circuit as claimed in  claim 2 , wherein a plurality of data signals are provided to the timing control circuit, and the data signals are pulse voltages. 
   
   
       7 . A liquid crystal display (LCD) driving circuit, comprising:
 a liquid crystal panel control circuit; and   a system control circuit configured for providing data signals and direct current voltages to the liquid crystal panel control circuit;   the liquid crystal panel control circuit comprising a timing control circuit, a direct current converting circuit, both connected to an direct current voltage output terminal of the system control circuit, the direct current converting circuit comprising a comparator, a reset circuit, and a DC-to-DC converting circuit connected in series.   
   
   
       8 . The LCD driving circuit as claimed in  claim 7 , wherein the comparator comprises a predetermined reference voltage, when the comparator receives a direct current voltage less than the reference voltage, the comparator outputs a low level voltage to the reset circuit, when the comparator receives a direct current voltage greater than the reference voltage, the comparator outputs a high level voltage to the reset circuit. 
   
   
       9 . The LCD driving circuit as claimed in  claim 8 , wherein when the reset circuit receives a low level voltage, the reset circuit does not work, when the reset circuit receives a high level voltage, the reset circuit provides a high voltage to reset the DC-to-DC converting circuit, that is, the DC-to-DC converting circuit is returned to an initial status. 
   
   
       10 . The LCD driving circuit as claimed in  claim 9 , wherein the timing control circuit comprises a plurality of electro static discharge (ESD) lines, each ESD line comprising a first diode and a second diode in series, positive electrodes of the second diodes being connected to ground, negative electrodes of the first diodes are connected to the direct current converting circuit. 
   
   
       11 . The LCD driving circuit as claimed in  claim 10 , wherein the predetermined reference voltage satisfies a relationship: Vc-0.7V<Vr<Vc, wherein Vc represents direct current voltage when the DC-to-DC converting circuit works normally, Vr represents the predetermined reference voltage, 0.7V is equal to a voltage drop when the first diode is turned on. 
   
   
       12 . The LCD driving circuit as claimed in  claim 10 , wherein the system control circuit comprises a direct current output terminal and a plurality of data signal output terminals, each data signal output terminal is connected to a positive electrode of the first diode of a corresponding ESD line. 
   
   
       13 . The LCD driving circuit as claimed in  claim 12 , wherein the data signal output terminals output pulse voltages, the direct current output terminal outputs a direct current voltage, amplitude of the pulse voltage is equal to a value of the direct current voltage. 
   
   
       14 . A liquid crystal panel control circuit, comprising:
 a direct current converting circuit, the direct current converting circuit comprising a reset circuit, and a DC-to-DC converting circuit, the DC-to-DC converting circuit having an initial status and a protection status, when the DC-to-DC converting circuit coming into the protection status, the reset circuit resetting the DC-to-DC converting circuit to the initial status.   
   
   
       15 . The liquid crystal panel control circuit as claimed in  claim 14 , wherein the direct current converting circuit further comprises a comparator connected to the reset circuit, the comparator has a predetermined reference voltage. 
   
   
       16 . The liquid crystal panel control circuit as claimed in  claim 15 , wherein when the comparator receives a direct current voltage greater than the reference voltage, the comparator controls the reset circuit output a reset control signal to return the DC-to-DC converting circuit to the initial status.